The present invention relates to a process for the desulfurization of isothioureas and isothioamides.
Most of the known procedures for converting thioureas or isothioureas to ureas involve hydrolysis with strong acid (See, e.g., Barlow et al, Journal of the American Chemical Society, Col. 78, pages 1258-1259) or oxidation (See, e.g., Kim et al, Novel Desulfurization of Thiocarbonyl Compounds Into Their Carbonyl Compounds With Tertiary Butyl Thionitrate, Tetrahedron Letters, Vol. 28, No. 15, pages 1669-1670 (1987)).
These procedures are not however suitable for all thioureas and isothioureas. More specifically, acid hydrolysis is clearly inappropriate for thioureas and isothioureas which are sensitive to acids. Oxidation procedures are obviously unsuitable for thioureas and isothioureas containing other oxidizable groups (i.e, in addition to the thiourea group).
It would therefore be advantageous to be able to desulfurize acid sensitive isothioureas and isothioamides and/or isothioureas and isothioamides containing more than one oxidizable group.